The present invention relates to a manometric instrument for underwater diving using a respirator.
In general, during such above mentioned dives, two different manometric instruments are consulted, of which the first is connected to the bottles of the respirator and provides, moment by moment, the pressure of the residual air within the bottles, whilst the second provides instant by instant the ambient external pressure expressed in meters of depth.
The whole of the data provided by the two above mentioned instruments has an absolute value only when the utiliser is at a depth from which he can ascend without requiring to include any decompression stops in his ascent, whilst it has a relative value in all other cases. In fact, if decompression stops have to be made the user must transform the "pressure" information with which he is provided by the instrument connected to the air bottles into "time" information in order to know if, on the basis of the other information provided by the other manometric instrument (actual depth and maximum depth reached) and by a chronometer (total immersion time), the air at that moment present within the interior of the air bottle is sufficient to allow him to ascend from the depth at which he is located.
The above described transformation requires not only the execution of relatively complicated calculation, but must be performed by the user in an absolutely accurate manner given that any errors whatsoever can involve often fatal consequences.